Expression by Lawsonia intracellularis

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• 作者：M. Pilar Alberdi ; Eleanor Watson ; Gina E.M. McAllister ; Jennifer D. Harris ; Edith A. Paxton ; Jill R. Thomson ; David G.E. Smith
• 关键词：Lawsonia intracellularis ; Obligate intracellular ; Pig ; Proliferative enteropathy ; Type III secretion system ; Pathogenesis
• 刊名：Veterinary Microbiology
• 出版年：2009
• 出版时间：18 November 2009
• 年：2009
• 卷：139
• 期：3-4
• 页码：298-303
• 全文大小：505 K

文摘

Contact-dependent secretion systems, such as the type III secretion system (T3SS), have been shown to play significant roles in the pathogenicity of many Gram-negative bacterial pathogens. Lawsonia intracellularis is a novel, obligate intracellular Gram-negative bacterium, which has been identified as the etiological agent of proliferative enteropathies in numerous animal species. Analysis of the genome sequence of the L. intracellularis strain PHE/MN1-00 has revealed the presence of a T3SS secretion system in this bacterium. In this study we aimed to determine whether this important virulence mechanism is also present in L. intracellularis strain LR189/5/83. Using a PCR-based approach, we verified the presence of a genomic region encoding a T3SS. Specifically, a gene highly homologous to the yscN energiser component of the prototypic T3SS of Yersinia spp. was identified and termed lscN. Two further open reading frames (ORFs) contiguous with lscN were also identified: lscO and lscQ, which are also homologues of ORFs within the T3SS of Yersinia spp. To establish whether this T3SS may be functional, expression was monitored directly by RT-PCR and indirectly by detection of serological responses in vaccinated and infected animals. Transcripts for lscN and lscQ were detected and purified rLscQ was recognized by antiserum from infected pigs, indicating expressionin vivo during infection. By analogy to other bacteria, this T3SS may be crucial for intracellular development and is likely to play a significant role in the virulence of this unusual pathogen.